Grinding machine



May 15, 1945. J. DECKER ETAL 2,376,236

' GRINDING MACHINE Filed Dec. 19, 1942 6 Sheets-Sheet 1 J. DECKER ET AL GRINDING MACHINE May 15, 1945.

Filed Dec. 19, 1942 6 Sheets-Sheet 2 A TO/P/VEX J. DECKER ET AL GRINDING MACHINE Filed Dec. 19, 1942 May 15, 1945.

6 Sheets-Sheet 4 5 Y M/ wpm w W WW 14% y 1945- J. DECKER ETAL GRINDING MACHINE a Sheets-Sheet 5 Filed Dec. 19, 1942 INVENTORS. j coapfcwp d f/X44 17 May 15,1945. J. DECKER ETAL GRINDING MACHINE Filed Dec. 19, 1942 Sheet 6 6 Sheets- Patented May 15 1945 GRINDING MACHINE.

I 'Jacobt ljecker-and-Bernard A; Kearns Cincinnati, hio,;assig nors to The..Cincinnati Milling'Machine 00., Cincinnati, "0hio,. a corporation of Application December 19, 1942,v Serial No. 469,158,

reas- This invention relates to-grinding machines and more particularly to improvements-in the-trans: mission and control mechanism therefor; I

One, of the objects of this invention'is to provide an improvedand simplified transmission for traversing purposes which may be infinitelyvaried as torate. v

Another object of this invention is to provide an improved hydro-mechanical transmission for grinding machines; I

A furtherobject'oi this invention isito improve the operation and control of a grinding machine by providing a single control for'causing 'ia'stap- I proach of the grinding wheelto'the work "and starting the reciprocation of the table for a traverse grinding operation and a second control for causin fast return of the grinding wheel and stoppage of the table after the grinding operation has been completed.

Another object. of this inventioniisto provide an improved manual :and powentransmi'ssion for a grinding machine table having suitable; interlocks for connecting anddisconnecting them so as to prevent manualfoperation during power operation and thereby .improvethesafety ofthe machine. j Another. "object of this 'invention 'isjto provide an improved power operable pick feed imec'zhanis n for automatic actuation from the table control transmission and'selective' with'respectgto sequential or.alternateoperationQj .A further object ofithis invention iis to. provide mean for automatically(reducing the torque c required for rotation of theinfeed'screwby'either the manual control or the pick feedmechanism.

' Other objects and advantages of the present. invention should be readily apparent'by reference to the following speci cation, considered inicon-f junction with the .accompanymgdrawings form-. ing apart thereof vandFit..-is to'be understood. that any ,rnodification'sniay b'einade in the exact structural details there. shown and described, within the scope of the appended claims, without departin from or exceeding the spiritof the in vention. v T I m Referring to the drawingsinwhichlike reference numerals indicate 'likeqorsimilar parts:

.Figure-lis 'a front elevation of amachine tool embodying the principles of this invention; 7

Figure. 2lisra vertical section 'Qnthe line 2 lot I Figure 1 showing; the mechanical, drive to the table. 1 .;Figune:*3 asectiononithe1inea3e=3rofi 3igm1e 1 showingthe' trip operable :revers'ing lnrechanism;

Figure -4ris a'section onthe line 4-4 of Figure L showing the starting control, lever.

"Figure 5.is asectiononthelin e 5.--5 ofFigure .4. Figure 6. is -asection .on the line 16,-6=of Figure'5. Figure. )7 is .a plan view of the control .ipanel on the vmachine.

Figure :8 is an .elevational view ,of the speedometer; for the table.

'Figure 9 is an. elevational. view:of. the pickieed 1o adjustment.,=dial.

. Figured!) .is .a-planv view of. the interconnecting linka-gerhetweenthe trip plunger and the reversing pilot valveQ I Figure '11 ista detail view of the pick feedratchet I5 mechanism.

Figure .12. is atdiagrammatic view .of the hydraulicfltable. transmission.

Figure. .13 .is :a continuation of the. diagram 7 shownin. Figure .12 -including thepick feed con- 'tro1 mechanism.

Figure 14.152. detailsection on the line I' l-l4 ofFigure 3. P g I Referring 'to gures 1 rand 2 of the drawings the reference numeral t0 indicates ingeneral the bed of the machine upon the top or which is formed .avflat guideway H and a v -guideway I 2 for receiving andguidingawork supporting table i3-forrtraversing movements relative. to a grind ing wheel 14 which is rotatably journaled upon azcrosssslide which is indicated generally by' the referencenumeral' -lfi. Thecross slide or Wheel headchas atself-'conta1ned transmission for rotating'the grinding wheel.

In the-middle front of the bed there "is mountedaicon'trol panel-l 6 upon'which is nested anti the ;c0ntrols;necessary to govern the operation of the machine. -'-It will be noted that these are conveniently-'- arranged as more particularly I shown in Figure Tan'cl that all are within easy 4. reach of the operator from his-normal position atithe frontof the machine. These variouscontrols are arranged between a manual control wheel l l for the wheel head and a, manual I control wheel' la -for th table. I I I Fcr'convenienee df explanation the table trans- I mission isshowndiagrammatically in Figure 12. Reierring to Figure 2, however, it will be seen that thetable is provided -onits underside with airack l ii that isxengaged -bya pinion 20 attached to the=upper end of ananti-frictionally supported shaft 2| mounted in the bed. The lowerend of this-shaftlisprovided with aworm wheel'22 that is driven'rby awormfl The worm ia isattached to. a Lshaft 14:" which :is interconnected by' bevel 12. This shaft terminates in a clutch member 2'! which is adapted to be engaged by a shiftable clutch member 28 splined on shaft 29. The shaft 29 is power driven'through a gear train 30 by a hydraulic motor 3|. The hydraulic motor is a constant displacement motor but is supplied by a variable displacement pump 32 so that by variation of the pump displacement an infinite change in rate may'be obtained.

The pump and motor are connected together by supply and return lines in what is known as a closed circuit in that the intake supply to the pump comes directly from the motor rather than action by the table the port 14 closes, thus gradfrom reservoir as is the case in an open circuit.

Means are provided for maintaining a pressure differential between the supply and return lines by supercharging the return line to a predetermined pressure which compensates for leakage and thus establishes a substantially constant operating condition.

To this end, the pump 32 which is unidirectionally driven has a delivery line 33 and a return line 34. The delivery line 33 is alternatively connectible by annular grooves in reversing valve 34 to. channels 35 and 36 which terminate in ports 31 and 38 of a start and stop valve 39. When the plunger 48 of the valve is in the start or running position which is that shown in Figure l2 the ports 31 and 38 are connected to ports 4| and 42 by annular grooves 43 and 44 respectively which are formed in the plunger 46. The ports 4| and 42 are connected by channels 45 and 46 to the motor 3|.

The reversing valve 34 has a pair of return ports 41 and 48 so that the remaining one of the pair of channels 35, 36 may be connected to return when the other is connected to pressure. The ports 47 and 48 are connected by channels49 and 56 to ports 5| and 52 of a pilot valve 53 which serves to control hydraulicshifting of the reversing valve plunger 54, and also to complete connection of port 5| or 52 to return channel 34. It will thus be seen thatthere are two parallel conduit systems extending from the pump to the reversing valveand that these two conduits are connected to the motor lines 45 and 46 by the reversing valve 54 either direct or in transposed relation depending upon the direction of table movement desired.

The pilot valve plunger 55 is adapted to be trip controlled from the table and toy this end the table is provided with longitudinally adjustable reversing dogs 56 and 51 shown in Figure l which alternatively engage a trip lever 58 shown in Figure 3 for rotation of a sleeve 59 to which it is connected. The sleeve .59 is provided-withgear teeth 60 which mesh with a pinion 6| secured to theupperend of a plunger 62 which is supported for rotation as well as axial movement. The rotation is utilized to effect trip operation of the pilot valve plunger. 55 and to this end the lower end of plunger 62 has a crank 63 keyed thereto as shown in Figure 10 and this crank is connected by a ball and socket joint 64 to a centrally pivoted lever 65. The lever 65 is connected by an adjustable link 66 to a bell crank 68 which has a ball ended arm 69 operatively engaging the pilot valve plunger 55. It should now be apparent that dog actuation of the trip plunger 58 will effect shifting of the plunger 55,

To insure complete shifting of the plunger. a hydraulic detent is provided by connecting a pressure line lllto port H in the valve bushing 53 and providing theplunger 55 with an enlarged.

ually restricting the return line from motor 3| and causing it to slow down before the point of reversal is reached.

The spools 12 and 13 are so related that just before the spool 73 completely closes the port 14,

the spool 12 has reached a point sufliciently past the pressure port II to permit the admittance of pressure on the other side of the spool and complete the shifting movement. This will result in port 1| being connected to port 15 and thereby through channel 16 to the tarry valve 17.

This valve has a V-shaped groove 78 which may be rotatably adjusted to variably restrict the flowthrough the valve and thereby vary the length of tarry at table reversal.

An interdrilled passage 19 connects groove 18 to channel 80 which leads to the right hand end of the reversing valve 34. Within the passage 19 is a check valve 8| which blocks the return flow through the valve, but a second check valve 82 is provided in parallel therewith but oppositely positioned to open under return flow whereby exhausting fluid may bypass the tarry valve.

. When the plunger 54 has passed through its center position it connects the pump line 33 to channel 36 and at the same time interconnects port 41 with channel 35 to reverse the direction of rotation of the table motor 3|. Attention is invited to the fact that between the time that the pilot plunger 55 has completed its shifting movement and before the plunger 54 has passed through center, the line 49, being connected to the return channel 34 of the pump 32, would tend to become vacuumized by the pump because connected to the suction side thereof and, therefore, to prevent this condition a differential valve 83 is connected across the channels 33 and 34 and adjusted to maintain a prescribed pressure differentialjbetween the two lines.

Thus, when the pressure in line 34 drops, for instance, and the pressure in line 35 rises due to inaction of the motor 3|, pressure fluid will be bypassed through the valve 83 from the line 33 to thev line 34 and thereby prevent such a condition from arising. Furthermore, the line 341s supercharged by a pump 84 which has a delivery line 85 that is connected to the line 34. The line 85 also has a branch 86 that is connected to a relief valve 81 for determining the pressure in line 85 which pressure should correspond tothe normal operating pressure desired in the line 34 taking into consideration its pressure difierential relationship to the line 33. This supercharging pump serves to replace losses due to leakage and insures against starvation of fluid in the line 34.

When the pilot valve plunger 55 is trip actuated in the'opposite direction, fluid pressure from port 1| passes through port 88 and line 89 to tarry valve 90 and then through channel 9| to the left hand end of the reversing valve 34 shifting the plunger 54 to the right.

The starting and stopping of the table'motor 3| is controllediby. the valve plunger! of valve.

' carcass 38 and this lplungerais shiftedhydraulicallyfrom I one position toith'e other under valve 52 which is manually operatediiby the operaton valve 92 has a pressure port 93 .which is supplied trom channel '10., which :numeral rep-v resents :in general the pressure line network sup p'lied' by a pump 194. :Inzthe running position, the port"53 is: connected .Ltuzport 5W and thereby through channel DS-to thelowerend of the start valve'fli. When th'evvalve 92 is moved upward the port Slis connected to port '96 and thereby through ichannel 81 to the upper end of valve. At that time the port '94 becomes connected to an exhaust por t 9B and return gchannels99 which leads-tore, low pressure relief valve-4:00;

The exhaust line till mm *therelief valveigoes to lanai-reservoir I02 from which the" pumps Mend Storm I'Ilui'd through channel-103. A's shown'in Figure ig the valve-92 is equipped with an operatlng' bell crank PM which has a socket l 0.5 in which is' fiftteda ball-shaped end III-8 of-fa pivoted starte ing lever I M; threaded stud. 18B isfiadjustably control of apilot positioned to limit the upward or stop movement of. the valve-92; while the plug -Il08inthe lower end of the "valve sleeve as shown in' Figur-e 12 limits the downward or -start movement of the val-ve 'fl'f' Inaddition, :a' :spring -pressed detent 109 is provided for selectively engaging notches I I and I II in the bell crank for holding the lever in either :one "of its two "positions. :Thus; if the lever 1:01 is pulled toward the -'operator,' the table starts; and by pushing it away from the operator or toward the table, the-table stops.

Th'e pump 32-is continuously d'riven :by a "prime" mover such as an electric :motor' m ans the armature shaft 113 of the motor 'has'a pulley I I4 whichis belt-connected to a pulley I I5 for also driving the pumps 94 and-84. Since the pump 32l other but when. theyare :both hym aulically urged towardone anotherutheir is-such asvto clamp thes-end 129. rigidly: between them; lithe sleeves are slidably mounted :in cylinders. 434 land 135. I-trshould now :be obviouswthat lit-"pressure is maintained in both cylinders 134 and 435 that the --cylinder :IZI9 willloezheld stationaryJIhis is the normal-condition. o

v-With the cylinder III 9 held .stationarynitiobe comes'possible-by changing the pressuralriconditions in opposite ends thereof to cause'imovement of the piston: I I8 and; thereby vary .Lthe displace ment of "pump 32; v This'is accomplished :by con-'- necting .the :ports rI-2I and 122.:byzchanniels 1Ii8 and I3! to ports I38 :and 'I-39ofaratecontrol valve =I4IJ. :This valve has apressurle port-I which is suppliedifrom the pressure channel 10 vand an exhaust port 142 which is connectedto the=low pressure return line 99. .7 H Thevalve has a rotatable plunger-.143 which in its normal position closes the ports Ill elnd I42; This would normally mean that fluid-would be trapped in opposite ends of the cylinder but should a, slight leakage take place thepis'ton I It might tend .to creepin one direction'or the other. v

'In order'vto maintain a constant pressure in spitevof these-ports being closed the pressure channel 10 has another connection throu'gh' are sistance I44, and iparallel branch' lins I 45=and I46 to the channels I36 and 1 31; Checle valves I41 'are interposed in the lines I45 'and 1-16 to prevent return escape of 'fluid-and-insureastead is continuously .drivenitwill be apparent that it is simply necessary to throw the valve 92 by the manual control lever I01 to-start reciprocation of the worksupportingftable. j

Thevariable delivery pump 32' 'is a -unidirec-' tional pump and its Volumetric output is varied from lzero to 'a predetermined maximum by a pintle il fixwhich is operatively' connected to :a controlrod I I I. This rod has a piston I 18 formed integral therewith which is slidable in a cylinder 1 I9, it'be'ing :noted that the rod extends through bothends of the cylinder-wherebyequal pressure in both ends of the cylinder will hold the piston stationary. I i

Thecylinder H9 is built as a unit and in turn is slidably mounted in a fixed 'sleev'e I20. This sleeve has a pair of independentports I-2-I- and I 22 formed on opposite sides' thereof and these ports communicate with axially extending-grooves +23 and 4 24 respectivelyiormed in opposite sides of the 'cylinder .I I9. It will be noted that these grooves are closed at both ends as 'shown'in the plan' view just above the sectional view.- The groove 123 has a=port' l25 at one end which communica'tes with one endchamber-of the cylinder 'Il 9,andithe groove I24fhas a' port I26 which communicates with the other end chamber of the cylinder. The cylinder I I9 isnormally held stationary by hydrau'lic means and this is 'accom-l plished by connecting one end of a -pivoted lever I21 at I28 to the cylinder, and interposing the other und I29 between a pairof fluid operable pistons I30 and I3I.

.Ihese'pistons are slidably mounted in centralizing sleeves I32 and I33, it being noted that the sleeves :havewa collarintegrally formed on one end which :limits their lmovem'entxtoward' one anier condition "In addition, the 'lines Iifi a-nd 'I 31 have branch connectionsthrough resistances I48 vto the reservoir line I0 I.*""I'he' efiect Oran this is that there is a source of pressurepa resistance to the flow to each end of thefcylindejr and independent resistances to "theescapeof fluid from the opposite ends of l the cylinder "whereby if the resistance"in" is equal to -the-resistance out the pressure in each end of the cylinde is equal to onehalf of the pressure in line "10 accordance with hydraulicprinciples; {Thcheck valves serve to prevent intercommunication from one end of the-cylinder to th otherand mak'e it possible to'use'only one ingoing resistance siic'h as the resistance I44; Itwillbe'noted that there is a continuous :fiow condition created which-is necessary -"in order to maintain predetermined pressures.

The valve plunger I43 has recesses' iorrned in opposite sides thereof and it should *no'wb'e evi dent that'if the valve is rotated to uncovergthe exhaust port 142- and therebyestablish cdtnf munication with port I39 for instance, the pressure port I4I-wil1beconnectedto port "I38, thereby permitting the introduction of additional fluid into line 'I'36-which would differentiate the pres sure with respect to-c'hannel 131 and cause move-'- of the valve the piston M8 will be hld' stationary in'its newposition; p I

"The rate control valve 113 has v'an' operating knob 1'49 located on'the control lpanlras shown in Figure'l. l

' order that the operator, may "know what the rate-setting is, a speedometer, indicated gen erally by the reference numeral *I 5Il in Figure 8, is mounted 0nthe front of the machine,-"=and the speedometer is driven iromithe :t'able transmission as follows. The shaft 24 shown in Figure 12:11am :spiral gear- 45i which intermeshes with nel I56 to port Therefore, as shown in Figure 8, the dial is provided with two sets of figures for indicating the feed rate in inches per minute, one set being for one direction of movement of the table and the other set for the other direction of movement of the table. Thus with the table traveling, the operator observes the dial and then rotates the knob. I49 to effect an increase or a decrease in the rate of table movement.

It is, of. course, necessary to intermittently interrupt grinding operations to true or dress the grinding wheel, which requires fast movements of the table for set-.up or positioning purposes and a very slow rateof table movement for the actual truing or dressing operation. In order that these Changes may be made without disturbing the setting of the feed rate mechanism, a separate control means is provided which has two positions, one of which will yield a rapid traverse rate and the other a slow or truing rate.

' To this end the cylinders I34 and I35 are connected to a rapid traverse vtruing control valve I54 having a plunger I55, positioning of which is determined by the axial movement of plunger 62 which as previously explained is capable of rotation or axial movement. This control means effects rapid traverse movement of the table by setting the pump at its maximum displacement, or a slow rate of table movement by setting the pump at a minimum displacement. In addition, means are provided for setting the pump to minimum displacement when the table is stopped by the start and stop valve.

The cylinder I34 is connected directly by chan- I51 of valve I54, while the cyl inder I35 is connected through a valve I58 and channel I59 to port I60 of the control valve I54. The plunger I55 is shown in the truing position whereby the ports I51 and I60 are connected to ports I'6I and I62 by annular grooves I63 and I84 respectively. channel I65 to annular groove I66 in the valve sleeve 39, which annular groove is connected to the pressure line whereby the port I6I is always under pressure. The port I62 is connected by channel I61 to port I68 in the valve sleeve 39 and when the plunger 40 is in the runnin position shown, the annular groove I69 connects the port I68 to the pressure port 10 which is formed in the annular groove whereby the port I62 becomes a pressure port. It will now be evident that channels I56 and I59 are connected to pressure during translation of the table, whereby the cylinder H9 is held fixed in the position shown by hydraulic pressure.

When the plunger 40 is shifted to a stop position it disconnects pressure from port I68 and connects it to an exhaust port I1I. Thus, the cylinder I35 is connected to exhaust and since pressure is still maintained in cylinder I34, the cylinder I I9 is shifted by piston I 30 in a direction to reduce the displacement of the pump 32 and thereby decrease the amount of oil being pumped during non-movement of the table which prevents the oil from becoming overheated. It will be noted that this result is obtained automatically through operation of the start and stop valve.

The trip lever 58 is pivotally supported on a The port I6I is connected by pin I1I carried by the rotatable sleeve 59, as shown in Figure 3, and is operatively connected by a pin I12 to a plunger I13. The lever 58 is mounted in a cross slot I14 formed in the end of the plunger and it has an elongated hole I15 through which the pin I12 passes whereby the lever 58 may be pivoted about the pin I1I to effect axial movement of the plunger I13 without binding. A ball handle I16 serves to operate the lever 58. The plunger I 13 is so connected that raising the lever 58 will efiect rapid traverse movement of the table, and lowering the lever will effect a slow movement of the table for truing purposes when the table is stopped.

The plunger I13 is operatively connected by a lever I11 to the valve plunger 62 for effecting axial movement thereof. The plunger I13 is normally held in a central position by a surrounding spring 406 which is interposedbetween a fixed plug 401 which also serves as a bearing for the lower end of the plunger and a washer 408 slidably fitted on the reduced portion 409 of the plunger. The washer engages a shoulder 4| 0, formed by reducing the portion 409, to exert an upward thrust on the plunger. The washer, however, is made large enough in diameter to engage a fixed shoulder 4 which limits the movement of the washer and thereby the plunger.

In addition, the lever I 11 is provided with a spring-pressed detent 4I2 as shown in Figure 14 which engages a depression 4I3 formed in the side of the lever which assists in centralizing the plunger. The detent also serves to engage the underside of the lever I11 when the plunger is moved upward to hold the parts in that position when the lever is released as in truing operations. It will be noted that during upward movement, the portion 409 merely slides through the spring 406 and washer 408, those parts remaining in the same position. A shoulder 4| 3 engaging the plug 401 limits the extent of the upward movement whereby the detent serves to hold the weight of the parts.

The valve sleeve I18, in which the plunger 62 slides, has a pair of ports I19 and I which are connected by channels I8I and I82 to opposite ends of the control valve I54 to effect hydraulic shifting of the plunger I55. The pump line 10 supplies a pair of pressure ports I83 and I 84 in the sleeve I18 and with the plunger 62 in its central position, the port I83 is connected by the annular groove I 85 to the port I 19, which hydraulically positions the plunger I55 as shown. At this time the port I 80 is connected by the annular groove I86 to an exhaust port I91 which is connected to the low pressure return line 99.

When the trip lever 58 is manually pulled upward it moves the plunger 82 downward and thereby interconnects the port I19 with the exhaust port I81, draining the upper end of the valve I54, and connects the port I80 to the pressure port I84 causing admission of fluid pressure to the lower end of valve I54, thereby shifting the plunger I55 upward to a rapid traverse position which in efiect servesto by-pass the start and stop valve. In other words, the pressure port IBI is connected to port I60 so that pressure is supplied to the line I59 regardless of the position of the start and stop valve, and the port I51 is connected to an exhaust port I88 whereby the fluid may drain through the line IOI to reservoir.

The pressure in line I59 flows to port I89 of the control valve I 58 which has a plunger I90 normallyheldiin theposition shown bya spring valve I54; When theivalve plunger I 55 1s moved upward port I98 is interconnected bythe annular groove I99 to port 200 and-[thereby to line- 36, and port I'9I is connected by annular groove 20 I to. port 202 and thereby to line 35 with the result that both of the motor channels 46 and 45 are connected: to the supply lines; 36 and 35 the same manner as if connected by the start and stop valve. p I

' Inotherwords, the effect is that the valve ear 223,

of'the table without interfering with the feed .rate setting;

Thetable may be traversed manually by the hand wheel I8which is connected through a gear train, indicated generally by the reference numeral 222 in Figure 12 to a worm and worm the worm being attached to a shaft 224.- This shaft carries a shiftable clutch member 225'- which is adapted to be moved into engagement withafixed clutch member 226 car-' ried by the shaft 228 in the proper direction, the

engages the clutch.

Similarly, the clutch 28located in the power driven to the-table is normally-held disengaged by asp'ring 230- operating on a piston 23I', the pistonbeing, connected by a piston rod 232 to a centrally pivoted lever 2331. This. lever' has a v forkz2-34 connectedto the clutch 28. A cylinplunger I55 has Icy-passed the start and-stop valve byconn'ecting the motor to its "pump and simultaneously increased displacement oi" the pump to effect rapid ope-ration of the motor 3I-.

When the table is'r'noved at a rapid traverse rate it is not necessary to utilize the tarry valves at reversal and therefore a c'onnection is provided whereby these tarry valves'may be automatically rendered ineffective. This connection comprises abranch line 203 from channel I02 "to port 204 ofa tarry by-pass valve 205= The channel I6 that leads from-thepilot valve 53 to the tarry valve 11 has a branch 206 which terminatesin port 201' of valve205-Qand the channel 89"that leads to the tarry valv 90 is connected to'a port 208 invalve 205.

-' When the plunger 209ofthi s valve is-shifted against the resistance of a spring 2 I0 which nor mally holds the valve in the position shown, the annular groove 2II connects port 208 to'po rt' 2I2 and thereby directly to line 9| leading tothe'jl'eft end of the reversing'valve. Similarly,i r'1"e po rt 201 is connected by annular groove 2I3 to port 2I4 and thereby to channel2|5 which leads directl'yto the righthand endaof the. reversing Va operation of the pilot valve 53*fluid pressure iwill ,fiow direotly to the reversingvalve and shiitjthe 'plunge r thereof without delay.

When the trip lever 58 is" moved downward to its truing position the pressure-port; I83 is connected to port ZIfi by groove Iand; thereby to channel 2I"l which "terminatesfirr port2l8 of valve l58; Admission'iof pressure? to this port shifts the plunger I90 against-the spring I91, thereby closing port I89 and interconnecting port I93 through the annular groove I-58- to the exhaust port 2I'9. This relieves the'pressure in cylinder I35'whereby the pressure still present incylind'erfIM shiftsthe cylinder H9 in a direc tion to reduce the pump displacement to arm- Fortruing operations it'fis. also not necessary to utilize' the tarry devices and ,thereiorecom nection are simultaneously made to render these ineffective lnthis case, the line 2!! has a branch connection220 to "port. 22VI of the. bypass valve 205 which will cause a shifting of theplunger 209 effecting the same connections as in the case of rapid traverse operation. whereby'upon actuation of the reversing pilot valve, the reversing valve will be immediately fired. It will now beapparent that the trip lever 58 may also be utilized to efiect fast or slow movement Itwi-ll now be apparent thatupon trip der 235contains the piston 23I,' and a cylinder 239 contains the plunger 221 and theends of these. cylinders are connected to a common chan-' nel 23 Iwhich is a branch of line I59.

Whenever line I59is connected to pressure by either the start and stop valve or the rapid traverse valve, the pistons: 23l and 22'! areactu ated in such a manner as'to disengage the clutch 225 and? engage the clutch 2-8, or, mother words,

to-disengage the manual driveand engage the power drive to the-table. This eliminates the possibility; of .the operator" attempting .manual operation while the, power is connected, and also. eliminates rotation of the hand wheel I8 dur'ing-power actuation' of the table for'reasons of. safety.

During traverse grinding, means have been provided for automatically pick feeding the wheel-head,;compri-sing a pick feed motor and a hydraulic control circuit-which is operable by the table reversing .mechanism. The pick feed motor comprises a cylinder- 238 containing a reciprocable rack piston 239 which operatively engages a pinion-240. The pinion 240 has a lever 24I integrally: connected thereto-,ythelever carrying :a pair ofpick feed pawls 242 and 243 as more particularly shown in Figure l1.- These pawls'are adapted to engage a pick feed Wheel 244 which iskeyedto asleeve 245.. A gear 246 also-connected. to the sleeve and wheel meshes with the gear: 241 which is operatively connected by a. clutch 248 to a shaft'249'. The shaft is connected by a coupling 250 to a shaft 25I which extends parallel to. the direction of movement or" thewheel slide. Thisshaft carries an elongated pinion 25-2 which isengaged by a gear 253 formed integral with the. cross slide feed screw 254.-- A nut 255 supported by a depending bracket 258 on the under side of the wheelhead engages the screw tion to the wheelhead.

Itshould now be apparent that upon reciprocation. of the piston 239 tha-t, a small movement may be-imparted to the wheelhead. Reciprocation of the piston 239 is controlled from the table reversing pilot valve 53. As previously explained, this-valvehastwo ports 15 and 88 which are alternately connected to pressure by plunger 55. Channels 89 and 206, which are connected to these ports, are extended to Figure 13 and connected to ports 25'! and 258- of apick feed selector control valve 259- which is shown in three 24. The clutch members are normally held engaged by ashifter 221 urged by a spring shifter 2.21 carryinga shifter fork 229 which 25.4 for impartingmomay be set to produce a pick feed only at either end of the table stroke, or it may be set to produce a pick feed at both ends of the table stroke. In the position shown it willefi'ect a pick feed at only one end of the table stroke.

In. accordance with the position of the table reversing pilot valve, the line 89 is under pressure.

but it will be noted that the port 251 is in communication with a T-shaped passage 26! which has no outlet and therefore no pick feed action will occur. The line 89 has a branch connection 26! which leads to an accumulator cylinder 262 having a contained piston 263'. One end of this cylinder has a port 264 which is connected by a branch channel 265 to a port 266 located in the end of the pick feed reversing valve 261. This valve controls reciprocation of the piston 239.

When pressure is admitted to the channel 26 l the piston 263 is moved in a direction to force the fluid ahead of it into the end of valve 261 shifting the valve plunger 268 into its right hand position. The fluid in the other end of the valve will escape through port 269 and channel 218 into a second accumulator 21! through port 212. The other end of this accumulator has a port 213 which is connected by channel 214 to line 206. Since this line is now connected to a low pressure return through the valve 55 it is possible for the piston 215 to be moved by the exhausting fluid.

Upon reversal of the pilot valve the line 206 will be under pressure, thereby shifting the piston 215 in the opposite direction and forcing the valve plunger 268 to the left and returning the accumulator piston 263. The pressure in line 206 will flow through the port 258 and the T-shaped passage 216 to port 211 and thus cause a pick feed action as follows. The port 211 has a channel 218 connected thereto which leads to a throttle valve 219 which may be adjusted to determine the rate of movement of the pick feed piston. This valve will effect a drop in pressure in the fluid flowing therethrough to line 280. This line is parallelly connected to ports 28!, 282 and 283 of the pick feed control valve.

Since the plunger 268 is now in its left hand position, the port 28! is connected by the annular groove 284 to port 285 and thereby to channel 286 which leads to port 281 of a pick feed stop valve 288. The plunger 289 of this valve is normally to the left of the stop position shown whereby the port 281 is connected by annular groove 290 to port 29! so that the fluid may continue through channel 292 to port 293 of the pick feed cylinder.

This will shift the plunger 238 to the right,

the fluid in the other endescaping through port 294 and channel 295 to port 296 of the pick feed control valve. Since the plunger 268 is to the left the port 296 is connected by annular groove 291 to a port 298. This port is connected by channel 299 to a second throttle valve 300. A channel 38! connects this valve to port 302 of the pick feed selector valve. It will be noted that this port is in communication with a longitudinally extending groove 303 which terminates in section 304 of the valve. In the position shown the groove 303 is in registry with a port 305 that is formed in the annular groove 386 in the valve bushing 301, and a return channel 308 is connected to this groove whereby the fluid exhausts to reservoir.

After the plunger 239 has completed its movement the pressure will rise in channel 280 and open a check valve 389 which is branch-connected thereto whereby the fluid will escape through line 3|0 to the left end of the pick feed control valve and shift the plunger 268 back to its right hand position. This will effect interconnection of port 282 with port 3!! whereby the fluid in channel 280 may now flow through channel 295 to effect return movement of the pick feed piston. The fluid ahead of the piston will return through channel 292, interconnected ports 29! and 281 of the pick feed stop valve, and channel 286 to port 296'. This port is now connected to port 3l2 which is branch-connected to channel 299 whereby the fluid will escape to reservoir through the throttle valve 308.

It will be noted that the fluid pressure entering the left end of the valve 261 for shifting the plunger 268 to the right may continue through the port 266 and channel 265 and shift the accumulator piston 263 to the lower end of its cylinder because the line 26! which is connected to the lower end of the cylinder is part of channel 89 which is connected to exhaust by the pilot valve 55. i

Attention is also invited to the fact that since the other accumulator piston 215 is at the top of its stroke and held in that position by fluid pressure from channel 286 that the fluid pressure cannot be forced into the accumulator because it has the same operating pressure and therefore the fluid will escape through port 3l3 and channel 314 to a low pressure check valve 315 which will open so that the fluid may continue through line 3!6 to port 382 that is connected to exhaust. Upon the next reversal of pressure in channels 89 and 206 no pickfeed will occur. This is the manner of efi'ectinga pick feed action at one end of the table stroke only. Should the valve plunger be rotated 180 degrees the same action will be produced for the right end of the table stroke with no action taking place at the left end of the table stroke.

Should the valve be rotated 90 degrees from the position shown, that is, in a counterclockwise direction, the connections are such that a pick feed action will take place at both ends of the table stroke.

In other words, the port 251 is connected to the port 302. and port 258 is connected to port 211. Should the line 89 be connected to pressure and the line 206 connected to exhaust by the table control valve, fluid pressure will enter channel 26! and shift piston 263 in a direction to shift the pick feed control valve plunger 268 to the right. At the same time fluid pressure will flow through the interconnected ports 251 and 302 of the pick feed selector valve to the throttle valve 380 and thereby to port 3l2.

Since this port is connected to port 296 the fluid pressure will continue to port 293 of the pick feed cylinder and shift the plunger 239 to the right. After this has been completed the fluid pressure will rise in channel 299 and open check valve 3H and thereby continue through channel 3! to the right hand end of the pick feed control valve, shifting the plunger 268 to the left. This will interconnect ports 296 and .298, whereby the fluid pressure will flow through channel 295 and-return the pick feed piston 239 to its starting position. The fluid in the left end of the pick feed cylinder will return the piston 263 to its lower position and then any excess fluid will open a low pressure check valve 3!!! whereby the fluid can escape to reservoir through line 206 which is an exhaust line.

Upon the next reversal of the table, line 286 will be under pressure, and line 89 connected to exhaust. This will cause actuation of the piston 'nected to, port. 'flow'through. channel- ZBB? to. efiect movement of surerises: in. channel 28 7 open: and; fluid. pressure "shift theflstop. plunger 28.9.

, atter the plunger. 289 .has-

i I v $816,236 21am cylinder Z'I I butthis will produce-inouresult the piston 268' i's already in Fluid: pressure will flow.

at the-tim'e because s left hand position.

however, through the interconnected ports 258 and-11%} of. the pick'feed selector valve to the throttle valvel'lfi and then continue through channel 2&0 to port .28 l This: port will be con- 285 whereby the fluid. will. again the pickfeedpiston. 2 3.9 to; theright. Astheepres: the check valve 309 will wilLfiow through channel 3") to the left end of the pick feed control valve; shifting; the plunger 2.6.8:,to the rig-ht the. port 282 becoming-contates-thegearzztttwhiclr is: connected as shown for rotation; of. the. pinion 2 52. Itwill. also .effiect a feed back through the sleeves2 45- which is-keyed tOSthe sleeve: 35.0 and thereby to the gear 3|9 which. is connected by an intermediate idler 32.0 to, an pinion 3-2 I. operatively. connected; with the hand wheel ll. The hand wheel if! is also operatively connected. tol a geartli. which drives through. the gear .32.4,--a gear 32-5. which carries. a

stop button 326... The, pick feed. stop. valve 2.8.8 is n 'ountedin the machine in the path of rotation .offthestop. button-whereby the stop button may Hydraulic detent means-are 'providedjwhereby moved; a certain distance an enlarged. 511001.321. will move, past the pressure 7 port .326

hold the plunger inthe. position shown.. 'After the stop'huttonhas beer'rrnoved out of. the path be repositioned by hydraulic :meansincluding :a control valve 329 which qhas ahl'e by. aknob 3'31. Theplunger has an annular groove 332 which is normally. in a' jp osition to interconnect a port '333 leading from I a port 334 ltmajted' in the'right hand end of the. control valve '288'to an exhaust. port 335.1. When the plunger is moved against the resistance or a spring 336a pressure port 33? isl interconnected by the annular roove-33am the port 1133;w,herel'a'y fluid pressure enters the rightend of'the stop valve to return 'the pl'unger 289 to a start or-run'ning position.

connected by gearing'SSQ to the shaft'ZBl. Fluid pressure is connected to-this motor at such a pressure. that the motor will exert a; torque on theishaft 251 and in the proper di-rection'toassist the'frotation but which is not-"great enough in itself to eiTect actual rotation. It is, therefore, ascrtof ccunterhalancing force which isnot suflicient. in itselfto completely overcome the resistances? involved but. greatly reduces the force tobe applied by the operating. agencies, Actuation of this motor is controlled bye reversing. valve 340 whichflhas ports 3 and-342 thatar connected to the motor by channels. 343

andfMd. respectively.. .This valve alsohas .a was sure, port 3.45:

P v v supplied by line loan'da pair of ez haust. ports 34.6 and. 3 41..

H whereby aite'r the port is reopened it will. complete a shifting. movement. and

a. plunger 330 that is opercQpluhser-ua of connects. to

I connected that it serves as. a

the .grinding wheel this. valve. is: operated by; a lever 36 9:- which is fries tionally connected-to the. sleeve; 2.45 that interthe ratchet wheel'ML-to; the: gear! 4.6,. Agclamping bolt: k determines the; amount of friction-and'ymust. be soadiusted that-the lever 349 .willturn. with the: sleeve until, the plunger 348:.is shifted. to one. of; its. extreme positions. into engagement: with either the ahutmentiil: or the end 353? or thevalve, after which-slippage takes place. Thus-the valve is. alwaysrin-.jeither ,a forward o1: a reverseposition; and the directlonal effect. on'the motor is in accordance with the direction of rotation otthe shaft-2.5.1. z I H In the: operation oi themachine, the table start and stop control lever H11 shown in Figure 4. is so single control lever toperform two functions, one. ofloringingv the grinding wheel: into the workand secondly, of starting the table on its traversing; movement. The rest. of the traversing grinding'cycleis. automatically performed inthe manner described, the table being automaticallyreversed at the end of each stroke and the-pick feed mechanismheing automatically operated until; ;-the. necessary amount oi. inffeed has been completed. at which time the, pick -.ieed,' mechanism is automatically stopped.

The table may be allowed to reciprocate a tow more. times. to insure. that thework isrounded up and brought. to theproper'siza. "When the, operator decides thatthel grinding operation h'asjb'een completed he merely has torotate the hand wheel IT the. necessary amount. tofeffect. retraction of I 'approxiniately vthe, amount that. itwas ted inby thepick feed. mechanismand inso, doing he stops thetable trarerseandefliects retraction of. the grindingWheel the. additional chine 'asshown} Figure? and locatedlrightbehind the lever itself.

" ment EigureA. means I06. ofthe lever moves in vanoppm v The. leverhas a hack position indicated bythe littleucircle 355. which indicates. thatythe. wheel head is back or. away 'from the work. the desirablev amountneces'sary for work clearance during loading.-

T e lever is pulled forward to the position ma cate'dfby the Circle355. to start the wheelhcad in. This.'corresponds.to the position of the ball ban.- dle 3.51 on the. lever. It will be noted that'the lever [01 is supported. at. 358, for universal move; that the. lower ballshaped end f site direction to the handle 3.5]. The lever may also. move crosswise from. the socket, l 05.1formed in the crank l 04 asshown in Figure Eito a socket 3'53 formed inajcrankifin withis operatively connected as, shownin Figure fi to an infeed control valve plunger 36!. When. the' control lever 1011's in the. back position indicatedby thefnumeral 355, the end 1061s in engagement with the socket .359 y and the bellcrankjfiflis rotated countefrclock wise from. the. position, shown aboutits support-'- ingpivot. 162 to sucha position thatithe. spring pre'ss'eddetnt 3fi3 fengages the, notch 3 64. and theplu'rigerdfii 'is/in its uppermost. position in engagement with a stop screw 365..

This, means that the valiie plunger 3.6 l is. moved upward fromthe position in which it. is shown in the hydraulic the proper direction, in

diagram, Figurelz, a 'sufll't'zientv has a pressure port 316, a pair of exhaust ports 311 and 318 and a pair of control ports 319 and 380. The port380 is connected by a channel 38I to a cylinder'382-1ocated in afixed part of the .bed containing a piston 383 which is integrally formed "on the end of the cross slide lead screw 254. This piston has a limited advance movement controlled by a fixed positive stop 254' and effects direct axial movement of the screw 254 as well as the connected gear 253 which slides.

axially relatively to the elongated pinion 252. The port'319 is connected 'by a channel 384 to a cylinder 385 which contains a piston 386. A piston rod 381 connects the piston to a fixed part of the bed of the machine and also serves to conduct fluid pressure to the chamber 388 located on one side of the piston.

I In this case the cylinder 385 is part of the moving wheelhead whereby it will become apparent that when the valve plunger 315 is to the left corresponding to the upper position of plunger 36I the pressure port 316 is connected to the cylinder385 and the wheelhead is retracted. It will now be evident that when the operator moves the lever from the position 355 to the position 356 he efiects rotation of the bell crank 360 in a clockwise direction moving the valve plunger 36I downward to the position shown in the diagram, thereby connecting pressure to port 312 which results in the plunger 315 being, shifted to the right. This immediately connects pressure to -channel 38I and thereby to cylinder 382 causing rapid advance of the wheelhead. This, of course, can be so adjusted that the grinding .wheel is about to engage the work.

' The control lever is thenmoved in a direction at right angles to its first direction of movement, or in other words, to the position indicated by the circle -389 on the diagram plate. This results in the end I 06 of the control lever I01 moving out of the socket 359 and into the socket I05 of the bell crank I04. The bell crank 360 will be held in the position shown by the spring pressed detent 363 while the lever I01 is out of engagement therewith. The lever I01 is moved forward again to the position indicated by the numeral 390. In so doing the bell crank I04 shown in Figure 4 is rotated in a clockwise direction, thereby moving the .valve plunger 92 downward to the position in which it is shown in the hydraulic diagram. Thisresults in a shifting of the start'and stop valve plunger 40 to a running position in which it is shown, whereby the table will begin its movement. It will now be apparent that the lever I01 may be utilized to bring the wheelhead into the work at a rapid rate and for starting the table.

. The lever remains in this position during the grinding cycle and after the grinding cycle has been completed the operator rotates the hand Wheel I1 in a return direction, retracting the grinding wheel approximately the amount that it was moved in by the pick feed mechanism and in so doing operates the control valve 340 which serves not only the purpose of causing operation of the booster pump but also has a pilot valve for controlling the position of a plunger 39I of an interlock valve 392.

amount that a pressure port 366 is connected to This valve-has a pair of control ports 393 and 394 which are connected by channels 395 and 396 to ports 391 and 399 located in the bottom of the infeed control valve and table traverse valve respectively vfor hydraulically shifting the plungers 36I and 92 respectively. In addition, the valve 392 has a pair of pressure ports 399 and 400 which are connectable by annular grooves in the plunger 39I to the ports 394 and 393 respectively when the plunger 39I is shifted to the left through introduction of pressure to port '40I which is branch connected to the booster motor control line 344.

The other line 343 is branch connected to port 402 located in the opposite end of valve 392 for shifting the plunger 39I to the right which is its normal position during operation of the machine.

There are also a pair of exhaust ports 403 and 404 to which the ports 393 and 394 are connected during the operating cycle whereby the plungers 92 and 36I may be freely operated.

When fluid pressure is admitted to ports 391 and 398 both Valve plungers 92 and 36I move upward. The movement of plunger 36I is limited by the stop screw 365.

The upward moving plunger 92 first engages a spring pressed plunger 405 slidably mounted in screw I08 and having ahead 406 which engages the inner end of the screw to limit'its outward movement. The spring 401 is compressed until the plunger. 92 hits the end of the screw I08. This aligns the sockets I05 and 359 whereby the lever I06 is returned to the socket I05 by spring 408. Upon a slight reverse rotation of handwheel I1 the valve 39I is shifted to the right which releases the actuating pressure from the ends of plungers 92 and 36I whereby the spring pressed plunger 405 will return the plunger 92' until the detent I09 engages.

The return positioning of these plungers stops the table by the shifting of the valve 40 and causes return movement of the cross slide because the plunger 36I in its return position connects pressure port 10 to port 361 and line 31I, shifting plunger 315 of the reverse valve 314 to connect pressure port 316 to port 319.

There has thus been provided an improved transmission and control mechanism for a grinding machine having infinite rate variation for the table, selective automatic pickfeed, unitary control for starting and stopping a traverse grinding cycle, and means contributing to the ease of operation of the wheelhead slide.

What is claimed is:

1. In a grinding machine having a support, a work table and a grinding wheel slide mounted on said support for relative movement, the combination of power operable means for advancing the slide toward the table, a control element for said power operable means, a second power operable means for reciprocating the table, a control element for initiating operation of said lastnamed power operable means, and a single control lever for sequentially operating said control elements.

2. In a grinding machine having a support, a work supporting table and a grinding wheel slide mounted on said support, the combination of means for controlling actuationof said parts including a first control element for initiating movement of the slide, a second control element for initiating movement of the table and a single control lever for actuating said control elements in sequence whereby the slide will move toward the table and then the table will be reciprocated.

wheel support including.

opera-blemeans for reciprocating the table in+ I table; a cross slide 3. 1111% grinding machine having a bed,;a:;wo1fksupportganda grinding wheel support recipro-' cablyfimounted" on the bed, the. combination'of fluid operable means for jshiftingfthe grinding eluding a start and stop-control Valve, and a single control lever operatively connected forcontrollingthe'position of both of saidjvalvesl I '4. Iniaigrinding machine having, a bed, a work fluid operable piston'having a. prescribdstroke for advancing the cross." slide; relative to- Ithe table,

awfl uid operable motor for reciprocating that-work a reversing valve, fluid 1 p g I having a'grinding wheel ,tatablymounted thereon, the combination of a table; a source ofr'pressure, and a'single'control lever operated valve-means: for connecting said pressure to'one side or said piston to advance the slide and to. effect connections to, said motor. to-

effectreciprocation of the .table'in a sequ ti l anner: 1

s 5; In a grinding machine having albed a, work supporting able and a grinding wheel support slidablymounted onjthe bed, said grinding wheel support, carrying a rotatable grinding wheel, the

, determined minimum displacement position, a start and-stop control valve for connecting said pump to said. motor, fluid operable means for shifting said control valve to a start position, and means for connecting pressure to said fluid operable means and-to both of said fluid operable lungers to set the pump at maximum dis-,

placement duringoperation of the motor.v

19x11"; a grinding machine having a grinding wheel support and a work supporting'table, the

, combination of means for eflecting. relative movenormally connected to pressure for shifting said control to, a minimum displacement position, a

combination of means for effecting sequential 1 relative movement between the table and the grinding wheel including a fluid operable piston for moving-theg'rinding wheel support, a source of pressure, a: control valve shiftable for connecta ingsaidpsource of pressure'tooneside ofvsaid piston to efi'ect advance of the grinding wheel v support, arotatablefluid operablemotor for shift ing the work-stable, a start. and stop" control valve for connecting said motor to asource of pressure,

fluid operable means for shifting'each of said said supports including a fluid valvesijin-a sequential manner, and a manually operable control leverior controlling said fluid operable means.

, 6- In agrinding machine having a rotatable grindingrwheel; and a work: support movable relative thereto, the'combination of adriving mem- Q I I berzfor effecting said movement, .a, power operable train including a prime mover terminating in said member, a manually operable train terminat ingisinlsaid member, a control clutch in eachof said trains; and power operablecontrol means for initiating actuation of said prime mover, en-

'gagem'entrofone of said clutches, and disengagement of theother clutch. g

-7.- a grinding machine having a grinding wheel and awork support, the combination with means forjeftecting relative movement between saidpartsincluding a fluid operable motor and a variable displacement pump for supplying said motor, of control means for effecting a major I change in the displacement of said pump from a predetermined minimum to a predetermined maximum; control means for connecting-said pump-to said motor in a, closed circuit, and a common control for said means operativly'bqnnected: to set' the displaceme t of said pump at a predetermined maximum. during connection of the pump to the motor and at a'pred'etermined minimum when the pump is' disconnected from said-motor. a -w I, 8; Inv a grinding machine having a, grinding wheel and a work supportfthe,combination of meansfor efiecting relative" movement between the supports includinga fluid operable motor connected to the table, a variable displacement pump" forsupplying fluid 'to 'said motor, a displacement control forsaidpump including a pair v connecting and disconnecting said motor to valve means forsetting said pump displacement '-valve means.

second plunger .for shifting saidcontrol to a maximum displacement position; control means for simultaneously connecting pressure to effect shifting of said valve, actuation of the second plunger and disengagement of said clutch.

l0pIn a grinding machine'having a grinding wheel and a work support, thecomblnation of means; for effecting relative movement between valve means for the means simultaneously controlled by said a variable displacement pump,:

at aimaximum during connection of'the motor and at a minimum during disconnection of the motonan auxiliary valve means for connecting said motor to the pump during disconnection thereof by said first named valve means, and means operable by the second-named valve means to set the displacement of the pump to a higher rate; than that set by thev first-named 11; In a grinding machine" having a grinding wheel and a work support, the combination-"of means-for eiiecting relative movement between the Wheel and the support including a fluid operof opposed plunge'rs;"meanstosupply pressure to said plungers to position 'saidcontrol in "a pie able motona variable displacement pump for supplying said motor, and control means for varying the displacement of said pump and thereby the rate of operationof: said motor in cluding a fluid operable piston, a cylindercom taming said piston. means for maintaining ba lancingfluid pressures in opposite ends of said cylinder .to'hold the piston against movement, rate, control valve operatively connected for changing the amounts oiifluidinopposite ends of the cylinder to change the position of said piston and thereby archange in the displacement or said'ipump;

In a grinding machine having agrindin'g wheel: and a work support; the: combination 01 means for effecting relative movement between.

the wheel and the support including a fluid operable" motor, a variable displacement pump for supplying said motor,. and control means for varying the displacement of saidpumpand' there;

, by the rate of peration of said motor including a fluid operable piston, a' cylinder containing said-- pisto'r1, means for maintaining'balancing fluid pressuresin opposite endsof' said cylinder to hold the'p'i'ston against movement, a rate con- I o'peratively connected r-tr changing the amounts 'offluid in opposite ends of the cyltrol valve operable motor,

inder to change the position of said piston and thereby a change in the displacement of said pump, and means responsive to rate changes of the motor to indicate the new rate effected.

13. In a grinding machine having a grinding Wheel and a work support, the combination of means for effecting relative movement between the wheel and. the support including a fluid operable motor, a variable displacement pump for supplying said motor and control means for varying the displacement of said pump and thereby the rate of operation of said motor including a fluid operable piston, a cylinder containing said piston, means for maintaining balancing fluid pressures in opposite ends of said cylinder to hold the piston against movement, a rate con- -trol valve operatively connected for inversely changing the amounts of fluid in opposite ends of the cylinder to change the position of said piston and thereby change the displacement of said pump, means responsive to operation of the motor to indicate the new rate effected, and means to move the piston and cylinder as a unit to effect major changes in the rate of operation of the work support.

14. In a grinding machine having a bed, a Work support and a grinding wheel support reciprocably mounted on the bed, the combination of fluid operable means for effecting relative movement between the supports including a source of pressure, a reversing valve, means connecting said pressure for shifting said valve'including tarry valve means, an auxiliary control for connecting pressure to said fluid operable means to effect rapid movement of the support, and means responsive to operation of said control for bypassing said tarry valve at reversals.

15. In a grinding machine having a'bed, a work support and a grinding wheel support reciprocably mounted on the bed for relative movement, the combination of a fluid operable transmission. and control means for effecting said relative movement includingmeans for eflecting said movement at a variable. feed rate, at a relatively fast rate, or at a relatively slow rate, automatic reversing means including tarry valves, a control for effecting said movement at said fast rate or said slow rate, and means operable by said control for rendering said tarry valves ineffective at either the fast or slow rate.

16. In a grinding machine having a bed, a work support and a grinding wheel support mounted thereon, the combination of power operable means for traversing one of said supports, rate adjusting means for determining a variable feed rate, a relatively fast rate or a relatively slow rate, reversing means, a control member therefor, trip means carried by the traversing support for rotating said member to efiect actuation of said reversing means,-a manually operable lever operatively connected for axially shifting said control member at will, and means responsive to movement of said member in one direction to effect said fast rate and in the other direction to effect said slow rate. I

17. In a grinding machine having a bed, a work support and a grinding wheel support mounted thereon, the combination of power operable means for traversing one of said supports, rate adjusting means therefor for determining a variable feed rate, a relatively fast rate, or a relatively slow rate, reversing means, a control member, trip means carried by the traversing support for rotating said member to effect actuation of said reversing means, a manually operable lever operatively connected for axial shifting of said control member at will, means responsive to axial movement of said control member in one direction to effect said fast rate, and in the other direction to effect said slow rate, and means to latch said lever in position for effecting said slow rate.

18. In a grinding machine having a bed, a work support and a grinding wheel support reciprocably mounted on the bed, the combination of a hand wheel operatively connected for advancing and retracting the grinding Wheel support, power operable' means for reciprocating the work support, control means therefor including a start and stop control lever for effecting reciprocation of the work support with the grinding wheel advanced, means responsive to rotation of the hand wheel in a direction to effect retraction of the grinding wheel support to effect shifting of said control lever to a, stop position, said means including a pilot valve, frictionally operated means responsive to the direction of rotation of the hand wheel for shifting said pilot valve, a source of pressure connected to said valve, and fluid operable means connectable to said source of pressure by said pilot valve for shifting said control lever.

19. In a grinding machine having a bed, a work support and a grinding wheel support reciprocably mounted thereon for relative movement, the combination of fluid operable means for shifting the grinding wheel-support, fluid operable means for traversing the work support, a control lever, a first valve operable by the lever for connecting pressure to the first-named fluid operable means, a second control valve operable by said lever for connecting pressure to said table traversing means, a manually operable control connected for actuation of the grinding wheel support independent of said fluid operable means, and means responsive to rotation of said hand Wheel in a retractive direction to effect shifting of said control, valves to a reverse position and simultaneously cause repositioning of said control lever.

20. In a, grinding machine having a work support and a grinding wheel support and power 0perable means for effecting a relative traversing movement between said supports including a pair of control channels, the combination with means for reversing the pressural conditions in said channels and thereby changing the direction of said traversing movement, of a pick feed mechanism including a selector Valve, separate connections from said selector valve to each of said channels, a pick feed piston operatively connected formoving said Wheel support, a reversing valve for the piston, a pair of throttle valves, independent connections from the selector valve to the respective throttle valves, a pair of lines extending from the reversing valve to opposite sides of said piston, means in the reversing valve for connecting said throttle valves to said pair of lines, and check valve means responsive to a rise in pressure in one of said lines after said piston has completed its stroke for connecting fluid pressure to shift said reversing valve and thereby cause retraction of said piston.

21. In a grinding machine having a work support and a grinding wheel support and power operable means for effecting a relative traversing movement between said supports including a, pair of control channels, the combination with means for reversing the pressural conditions in said channels and thereby changing the direction of gversing valve to effect i upon reversal of pressural conditions in said of said lines after said reversing valve and said piston,

said traversing movement, of a pick feed mechanism including a selector valve, separate connections from said selector valve to each of said channels, a pick feed piston operatively conpair of throttle valves, in-

irom the selector valve extending from the reversing valve to opposite sides of said piston, means in the reversing'valve for connecting said throttle valves to said pair of lines, check valve means responsive to a rise in pressure in one of said lines'after said piston has completed its stroke for connectingfiuid pressure to shift, said reversing valve and thereby cause retraction of said piston, and means connecting said channels to opposite ends of said re- "tial shifting thereof channels.

22 In a grinding machine having a work support and a grinding wheel support and power op- ;erable means for effecting a relative traversing movement between said supports includin a pair of control channels, the combination with means for reversing the pressural conditions-in said channels and thereby changing the direction ofsaid traversing movement, of a pick feed mech anism including a selector valve, separate connections from said selector valve to each of said channels, a pick feed piston operatively connected for moving said wheel support, a reversing valve for the piston, a pair of throttle valves, independent connections from the selector valve to the respective throttle valves, a pair of lines extending from the reversing valve to opposite sides of said piston, means in the reversing valve for connecting said throttle valves to said pair of lines, check to a rise in pressure in one piston has completed its stroke for connecting fluid pressure to shiftsaid valve means responsive means connecting said channels to opposite ends itial shifting thereof upon reversal of pressural conditions in said channels, and means in said selector valve forselectively disconnecting one or the other of said channels from its respective throttle valve whereby said pick feed piston will be operated on alternate changes in pressure in said channel.

23. In a grinding machine having a work support and a grinding wheel support and power operable means for effecting a relative traversing movement between said supports including a pair thereby cause retraction of said traversing movement,

ofcontrol channels, the combination with means for reversing the pressural conditions in said channels and thereby changing the direction of of a pick feed mechanism including a selector valve, separate connections from said selector valve to each of said channels, a pick feed piston operatively connected for moving said wheel support, a reversing valve for the piston, a pair of throttle valves, independent connections from the selectorvalve to the respective throttle valves, a pair of lines extending from the reversing valve to opposite sides of said piston, means in the reversing valve for connecting said throttle valves to said pair of lines, check valve means responsive to a rise in pressure in one of said lines after said piston hascompleted its, stroke forconnecting fluid pressure to shift said reversing valve and thereby cause retraction of said piston, means connecting said channels to opposite ends of said reversing valve to effect initial shifting thereof upon reversal of pressural conditions in said channels, and means in said selector valve for selectively disconnecting one or the other of said channels from its respective throttle valve whereby said pick feed piston will be operated on alternate changes in pressure in said channeLsaid selectoryalve also having an-.

' port, control means other position for disconnecting both of said channels from said throttle valves to prevent operation of said pick feed mechanism.

24. In a grinding machine having a bed, a work support and a grinding wheel support mounted on said bed for relative movement, the combination of a first power operable means for advancing the grinding wheel support, a second power operable means for reciprocating the work support, a-source of power and a single control lever for causing sequential connection of said source of power to each of said power operable means in the order named.

25. In a grinding machine having a bed, a work support and a grinding wheel support reciprocatably mounted on the bed, the combination of a hand wheel operatively connected for advancing and retracting the grinding wheel support, power operable means for reciprocating the work suptherefor including a start and stop control lever for effecting reciprocation of the work support with the grinding wheel advanced, and means responsive hand wheel in a direction to effect retraction of the grinding wheel support to effect shifting of said control lever to a stop position.

JACCB DECKER.

BERNARD A. KEARNS.

to rotation of the 

